Automatic latching means for back rests



Jan. 15, 1957 E. A. HERIDER ET AL. ,77

AUTOMATIC LATCHING MEANS FOR BACK RESTS 4 Sheets-Sheet l A Filed Oct.

. INVENTORS.

Elmer A. Her/'der I Kenngrd Pitts L THE/R ATTORNEYS 15, 1957 E. A. HERIDER ETAL 2,777,504

AUTOMATIC LATCHING MEANS FOR BACK RESTS 4 Sheets-Sheet 2 Filed Oct.

m M w .mfna W0 V nn .1 H

Jan. 15, 1957 E. A. HERIDER ETAL 2,777,504

AUTOMATIC LATCHING MEANS FOR BACK RESTS 4 Sheets-Sheet 3 Filed 00L 24, 1955 mw s N T H H R 4 8 4 N 4 0 N 5 6 I r mm m Jan. 15, 1957 E. A. HERIDER ET AL 2,777,504

AUTOMATIC LATCHING MEANS FOR BACK RESTS 4 Sheets-Sheet 4 Filed on. 241, 1955 INVENTQRS. flmer A. Her/der By Ken/70rd Pit/s THE If? A T TORNE Y5 United State Ira AUTOMATIC LATCHING MEANS'FORBACK.

REsrs.

Elmer; A; Herider, Dearborn Township, Wayne County, andtKennard Pitts,.. East: Detroit; Mich, assignors to .R'Dfi W l Spring and Aide: Company, Goraopolis, Ea

a Benusyl ia orpora i n Application, octobe zag 1955, Serial No. 542,34s-' 13 Claims. ,(cl, less-.162),

movement such, that. it inherently assumes, a particular adjusted position,

Hitherto, known forms ofseats having tilting back rests have found particular utility} in the automotive, field, being there useful as, ameans QnWhich to seat a, frontoccupant of. a' two-door sedan, for instance, and; at the. same time, heingfoldable out of the way when the seat isunoccupied so as to permit free access between the. rear of the sedan and' either one of'the opposite two. doors: thereof. The feature of adjustability is much. sought after butrarely, if' ever, provided in tilting back rest constructions by reason of the fact that the usual latchingmeanssemployed presents a certain imped ment to the'free. and easy. operation of the back rest in foldingit out of the, Way. MOI$1 over, there; are. usually several: adjusted posi'tionsbetween which an; adjustable, back restv selectiyely is moved and, ordinarily, when the, back rest is. unfolded, it is. desirable that it be, restored. to its completelynormalposition rather than to an intermediate: forward position or to an.inter-. mediate rearward position withrespect to. normal,

It, is an object of the present-invention to. provide a folding. adjustable back rest and to provide dual. controls, therefor which permit ready control of this back rest in disengaging. the same for folding. motion from either a position forwardly of the structure. onwhich it ismounted, or rearwardly thereof.

It is a further object of the. present, invention. to provide a folding adjusted back rest as defined in, the preceding o j herein the. back re t n nfolding; selectively as.- surnes. a normal position automatically; even though several available, intervening forward positions, and rear positions relative thereto are. also availablev into. which the back rest may be selectively adjusted, at willbutnot auto.- matically.

Further features, objects, and. advantages. will either be specifically pointed out or become, apparent, when, for a better understanding of the invention, reference is, made to the following description taken. in conjunction with the accompanying drawings in which, in general:

Figure I is a. perspective, view of onev side, of a seat structure embodying the present latching, plunger mecha= nism which is shown in meshed. plate condition having the plunger plate. advanced;

Figure 2. is aperspective view of the structureofligure. 1 but from a different. side and showing, the. device. in separated plate condition with the plungerplatev re,-

-tracted;

. 2 n. a. diiferentj slottiu the striker plate namely, he on Slot; p

Figure. 5, is..a plan view corresponding to. Figure 3. but with the striker. plate and the, back rest folded out of the vicinity of the, plungerwhich is in advanced meshed plate condition;

Figure 6 is a sequence view, following the Figure pcsi-tion and showingfthe, approach of the striker plate; and Figure. 7; corresponds to, Figure land forms a. sequence view. following the Figure. 6 position, Y

Inmore particular reference to. Figure, L .of the; drawings, a seat structure 10-is shown having a full. width seat cushion. framework including. a hollow front rail 12 a hollowrear rail 14* and a pair of opposite. rails connecting thefront and rear railsat their opposite. ends, one. ofthe side rails. being shown at. 16, and having. a hollow cross section. The side rail 16.may bewelded at'1 8. to theyadjacent endof. the front rail. 12 andrnay. be weldedat 2.0 tothe corresponding end of the rear rail 14. Intermediate the opposite ends of. the rear rail 14, a. forwardly and diagonally upstanding bracket 22 is welded thereto at'24. and is aperturedtoprovide. a pair of spaced apart; bearing. openings in which the pivoted. endof a bent back rest pivot bar 26 is received and adapted, to rotate. The, backrestpivotbar 26 isreceived in aligned openings adjacent the juncturehetweena centralvertical. rail. ZSQanda lower horizontal rail. 30..forming part of a fol ing. adjusted. back rest frame; The back restframe is. generally. rectangular in, shape and, in addition toi the, central vertical rail 28., the framework. includes. an out-v i e ertica r A.. 1ia t u c ure b tw en t e ou si e. t ca rail an he ow h r n z rail-10,,

' may be-ofltruhber! and whichis securedpthereto'by means of a Self-lappi screw. 38. p v

Relative swinging movement of the back rest frame in the:counterclockwise, direction as viewed in Figure l' immediately arrested in a reclining position. as, soon as, the cushion.3,6, engages, a; confronting metal. plate40 in the. path thereof whi cli is secured. as by means of screwsto. an adjacent portion. of the stationary rear seat rail 1,4,. The. outside vertical rail 32. is L-shaped' at its lower endso as to present a generally forwardly extending striker plate portion 42, having; alongitudinally extending slot. 44 formed in the, extreme or toe end thereof. .The.

side; rail 16.is apertured, to provide a pair of spacedbearings,.not' shown,, which; carry a rockable pivot: bar io having its end milled; fiat: on: botlrsides and: protruding through theslot 44 inathe foot.42. The protruding milled end of the, pivot bar- 4.6; is apertured' and is retained- Within, the slot as by-means of acotter pin 48, passing through the aperture. A spiral leaf spring 50 surrounds the pivot bar 46 and hasgi ts. innerend secured to thelatterformovement therewith. The outer endv of. the spiral leaf spring50 hasa radially extending. tab 51 stationarily. anchored-to. the side rail16, in an opening there provided and maintaining the spring undertension in amanner to tend; to unwind itand Continually stress. the back rest frameformotion inv a counterclockwise or forward di-. rection: as viewed in Figure 1, that is, to move the backrestinto its foldedposition- The back rest frame is; normally held in an adjusted position by means of a lockingdevice 52 having a beveled latching plunger nose-54 which engages-the strikerLp la te portion-of the L-shaped outside vertical rail 32. The plunger nose 54 is actuable' for. retrac o by ans. et P r of. d er B el cab s-5 S-W im e conn e o ui ble" operator- P e ed,.re u teeeb e re eas me a i m o of wh illu trated: at 6.0-. he cable rel se-m ch nism 60.

includes a depending standard 62 secured to the bottom of the front rail 12 spaced from the weld juncture 18 and carrying a pivot bar 64. The pivot bar 64 pivotally supports the rear end of a heel actuated pedal 66 disposed near the base of the seat frame at one corner thereof and actuatable by the heel of the occupant of the seat.

Operation of the pedal 66 of the cable release mechanism 60 by depression causes the plunger nose 54 to be withdrawn from any one of a row of long and short slots 68, 70 with which it registers in the striker plate portion 42 of the L-shaped outside vertical rail 32 of the back frame adjacent the juncture of the rail with its portion 42. The short slots and the long slots 68, 70, are in a row conforming generally to an arcuate path 72 described and laid out about the axis of the pivot bar 46 as a center. Swinging movement of the back rest frame and the outside vertical rail 32 causes the path of the row of slots to conform to exact alignment with the arc of a circle except for the long shot 70 which can be seen to have a rearward or lateral extension portion, Figure 1, extending outside of or beyond the exact row of the slots. Adjacent the juncture of the outside vertical rail 32 and its striker plate portion 42, a laterally deflected ramp or flange 74 is provided in the latter portion 42 which is in the line 72 of the arcuate row of slots and which is deflected outwardly of the seat structure 10 so as to define a hereinafter described wedge or cam surface at its inner face.

In conventional fashion, the dual cable controls may selectively be operated from either the front or the rear of the seat structure 10 to actuate the appropriate Bowden release cable 56, 58 and retract the plunger nose 54 of the latching mechanism such that the back rest frame may be inclined forwardly or rearwardly about the pivots 26, 44 whereupon the plunger nose may be restored to advanced position in the adjacent slot opposite thereto in the striker plate 42.

In Figures 2, 3 and 4, the plunger nose 54, which is adapted to protrude through either the short slots 68 or the long slot 70, is shown to be integrally formed at one end of a substanu'ally L-shaped plunger plate 76 which is provided with a pair of spaced identical teeth 78 in one side thereof. The shorter leg of the L-shaped plunger depends as indicated at 80 and is formed with an aperture through which a return spring 82 is suitably secured at one end, the return spring 82 being anchored by means of a stopper at the opposite end to the seat frame side rail 16. The seat frame rail 16 supports the lower one 84 of a pair of vertically spaced horizontal plates thereabove which slidably carries the plunger plate 76 and which also carries a companion L-shaped plate 86 forming an actuator plate. The actuator plate has a main single tooth 88 formed in the side thereof complemental to and adapted to be straddled by and mesh with the adjacent respective teeth 78 on the plunger plate 76 and also has a pair of spaced apart longitudinally aligned slots 90 formed ,centrally thereof. The slots 90 receive a vertical pair of spaced stationary guide pins 92 which are anchored at their base in the plate 84 and which are anchored at their upper ends in the other horizontal plate 94 appearing above the companion plate 84 in Figures 1 and 4. The L-shaped actuator plate 86 has a short depending leg 96 suitably slotted at 98 and 100 to receive the stopper carrying anchored ends of a pair of respective slide wire elements 162, 104 carried in the respective Bowden release cables 56, 58. A helical return spring 106 is se cured in a suitable aperture in the depending leg portion )6 of the actuator plate 86 and is firmly anchored to the frame side rail 16, Figure 4. Between the upper and lower stationary plates 84, 94, a vertical pair of spaced apart pivot pins 188 and 110 is received which pivotally supports a pair of symmetrically identical bell cranks. Each of the bell cranks has an arm portion 112 in engagement with one side of the plunger plate 76 and another arm portion 114 which is connected to the correone of the slots in the striker plate.

sponding arm portion on the adjacent bell crank by means of a common helical return spring 116. The helical return spring 116 is continually under tension so as to tend to foreshorten between its opposite ends and draw together the adjacent arm portions 114 of the bell cranks and force the other arms 112 into tight engagement with the plunger plate 76 in a direction normal to the surface thereof.

The upper one of the two stationary plates 84, 94 is suitably slotted at 118, Figure 4, to permit sliding movement of the plunger nose 54 through the slot and also some sliding movement in a direction laterally of the slot. When the plunger 54 slides laterally of the slot 118, it encounters, according to Figure 2, a metal shelf as diagrammatically indicated at 120, preventing its advancement and entry into any of the slots except the slot 70 which is the longest In assuming such laterally oifset position, the plunger 54 is free to travel relatively up and down the inner wedge surface portion indicated at 122, Figure 4, presented by the inner surface of the flange 74 and thereby to be wedged in so as to retract inwardly generally in the direction of its own axis.

The motion just discussed is illustrated in the sequential Figures 5, 6, and 7. In Figure 5, the plunger plate 76 and the actuator plate 86 are shown in meshed position wherein their respective teeth are meshed and wherein the plunger is advanced to a position in an unoccupied area in the path of the striker plate portion 42 of the outside vertical rail 32. It will be noted that the respective teeth 78, 88 between the sides of the two slidable plates cooperate to define spaced sets of transversely engaged lug portions 124 and spaced sets of cam surfaces 126 which provide for a one-way connection between the two plates. That is to say, when the actuator plate 86 is withdrawn. to the rear in the direction of the arrow 128, Fig ure 5, the lug portions 124 engage so as to carry with them the plunger plate 76. Retraction of the plunger plate 76 upon engagement of the same with the wedge surface 122 of the striker plate portion 42, causes the cam surfaces 126 to slide diagonally against one another and force the plunger plate during its retractive movement in the direction of the arrow 128 to move also in the direction of the bell cranks against the resistance of their return spring 116. This condition is brought about due to the retraction of the plunger plate 76 by the engagement therewith of the wedge surface 122 in Figure 6. When the leading edge of the striker portion 42 which carries the flange 74 comes into the vicinity of the plunger 54, a resulting engagement occurs between the ramp shaped wedge portion 122 on the inner face of the flange and the tip of the plunger nose 54 which is beveled. The

. wedge surface 122 wipes across the nose of the plunger and causes the plunger plate 76 to commence to retract toward a final position, according to Figure 7. In Figure 7, the bell crank return spring 116 is stretched to its fullest extent, the mating lug surfaces 124 between the teeth are separated, and the cam surfaces 126 are in a fully extended position such as to assure that the plunger plate 76 is laterally separated from the actuator plate 86. In its laterally displaced position in Figure 7, the plunger 54 carried by the plunger plate 76 is laterally ofiset from the row of the slots in the striker plate position 42 and will enter in and engage only with the longer slot when the latter is opposite thereto.

According to the positioning procedure in the simple and direct manual operation of the foregoing latching mechanism, the sequence of positions is illustrated by the respective preceding Figures 1, 3, and 4 in that order. From the position of Figure 1, the actuator plate and the latch plate 86, 76 are retracted together to assume the position of Figure 3 with their teeth in mesh and the plunger nose 54 is withdrawn from whichever slot in the striker plate row with which it was registered. The back rest and the striker plate portion 42 are 1'0 tested as a unit by the seatoccupant to a new position of registry for the plunger nose 54 whereupon the plunger is allowed to. pass into. the slot according to Figure 4, which happens, to show the plunger received inthe long slot 70, corresponding normal position,.altho.ugh any other slot is satisfactory whenever the plunger registers. therewith.

It may be. noted that if. the. plunger platev 76 and the actuator plate 86 are withdrawn from: the advanced position showing of Figure: 1 and the striker plate is thereupon rotated into a position such thatno slot is opposite to. the nose 54 when the actuator-plate. 86v is subsequently released, the. plunger. plate thereupon-is no.v longer able to advance therewith because the plunger plate path is blocked by the metal shelf 12d of the striker plate 42 and the actuator plate. 86 will not advance because of the friction involved at points 126 between the actuator plate and the plunger plate 76., the friction involved betweenthe plunger plate nose 54 and the striker plate. 74, also the side pressure applied by the bell cranks 114 at point 112 upon the plunger plate because of the spring pressure (116-). But both plates 76 and 86. will maintain their positions at the time of. release until the: striker plate 74 is rotated and the plunger 76, contacts a slot, thenv both the plunger plate 76 and the actuator; plate 86 will move forward together into an advanced position.

Separation between the-plunger plate 76 and the actuator plate 86 may be accomplishedin only one. manner.

The plunger and actuator plates are. manually retracted from the position of Figure 1 into the position Figure 3 by means of the Bowdenrelease cables 102, 10.4 where.- upon the back rest frame is forwardly folded and the striker plate is rotated therewith out of the way so as to be absent according to Figure 5. Subsequent release of the plunger plate 76 and the actuator plate 86 by operation of the Bowden release cables causes the plunger nose 54 to block the arcuate path of the striker plate 42 when it reapproaches the area of the plunger.

Accordingly, the cam surface 122 on the leading flange edge 74 of the striker plate engages and wipes acrossthe plunger nose 54 to cause the obstructing plunger, to retract and move laterally according to the position of the showing of Figure 7. In this case, the plunger nose 54 slides laterally and rearward because of the wedge locking device 52 and Figures 2 and 4, inthat order,

show the sequence of restoration, that is, from the position of' Figure 2 where the path of poised plunger is blocked by the line of metal indicated at 120' on the striker plate 42. The shelf portion 120 of the striker plate wipes across the nose of the plunger to a point at which the latter registers with the long slot 70 so as to advance thereinto and engage according to the. showing of Figure 4. So advanced, the plunger takes a diagonal path under the. urgings. of the spring biased bell-cranks and resumes its normal meshed position with the actuator plate 86 in alignment with the row of slots. 68, 70. according to the path 72.

The plunger may also be restored from its poisedposition of Figures. 2 and 7, according to the sequence of Figures 2, 3, and 4, in that order. That is to say, by suitable actuation of the cables 102 or1Q4 by the operator beginning with the position of the solid line showing of Figure 2, the actuator 86 is retracted against the opposition of the return spring 106 and the slots 90 in the actuator plate 86 slide rearwardly alongtheir staa rmen;

tionary guide pins 92. The cam surfaces 126 permit the latching platex76 to be diagonally restored to meshed condition with the retracting actuator plate 86 under'the urging of the bell cranks suchthat the plates assume the retracted meshed condition of Figure 3. Thereafter, the actuator plate may be released for advancing at a time at which the plunger plate 76 registers with one of the short openings 68, or else the long opening" 70, as particularly shown in Figure 4, whereupon the plunger nose 54 will enter the appropriate opening to latch the striker plate when the plates. 76, 86 advance together.

It is apparent from the foregoing description that'the presently. disclosed adjustable folding back rest is of particular utility in its application. to the front seat of a twodoor' automotive. sedan. wherein it maybe released for folding. from either the front or the rear thereof and whereby it normally resumes, under-the action of the return spring 50,. its restored normal position. by-'auto matic. selection of the longxslot interposed among the various short slots. 6&. at each. side thereof.

As herein. disclosed, the. invention is shown embodied in a. seat .and back rest construction wherein the seat connected locking device 20- is stationary and the back connected latching plate 42. is swingable with the back. It is evidentthat. by means of a simple reversal of parts, the; latching plate 42 may be seat: connected and held stationary, whereas the locking device. 52 may be employed as the swingable part by being connected to the swinging back. The cam wedge surface 122' on the latching plate in either. case will selfrevidently. function. the same in; its relative wiping motion with respectto. the end of' the. retractable plunger nose. 54.

Variations within the. spirit and scope of. the invention described are. equally. comprehended by theforegoing description.

While we. have described presently preferred embodiments of: our invention, it is to. be understood that it. may be otherwise embodied within the scope of the following claims.

Weclaimz.

l. Latching means comprising a swinging striker plate provided, with a row of spaced plunger receiving means in series alignment with one. another in the direction of swing, a. stationary locking device confronting the striker plate during a portion of its swing andprovided with a self-advancing biased plunger having a normal protruding position disposed in the path. of the row of plunger receiving means for selective latching registry therewith to, lock-the striker plate in adjusted positions against movement, at least one of said plunger receiving means having a portion laterally olfset from the row, and means for retracting and deflecting the plunger laterally of the path of. the. row in the direction of the aforesaidv lateral offset such. that it registers only with and automatically advances only into said one. plunger receiving means.-

2. Latchingmeanscomprisinga movable striker plate provided with a rowv of spaced plunger receiving openings in series alignment with one. another in the direction of travel of the plate, astationary locking device confronting the. striker plate during aportionof'its travel and provided Witha plunger having a normal protruding position disposed in the path of the. plunger receiving openings, at least one of said plunger receiving openings extending laterally out of alignment withthe row, and means for retracting and deflecting the plunger laterally of the path of' the row in, the direction laterally out, of alignment with the row such that it is capable of registeringonly with and automatically advancing only into the said one plunger receiving opening. v I v 3. In a latching means comprising a movable member provided with a row of spaced plunger receiving slots in series alignment with one another in the direction'oftravel ofthe member, a stationary locking device confronting the member during a portion of its travel and provided with a' self advanci'ng biased plunger having a normalprotruding position disposed in the path of the plunger receiving slots for selectively engaging the slots to lock the member in adjusted positions against movement, the improvement which comprises a laterally offset slot extension provided in at least one slot, and means for retracting and deflecting the plunger laterally of the path of the row in the direction of the aforesaid ofiset slot extension such that it registers only with and automatically advances only into said one plunger receiving slot.

4. A seat frame and folding back frame construction for a seat comprising a striker plate carried by one of the frames and provided with spaced slots disposed in a row, a locking device carried by the other of the frames so as to confront the striker plate during a portion of the relative movement between frames, said locking device having a self-advancing biased plunger arranged to selectively register with the successive slots in the row, at least one of said slots having an extension portion extending laterally of said row, first cam means effective between the plunger and said plate to cause the plunger automatically to retract during predetermined relative movement between the frames, and second cam means in the path of and engageable with the plunger during assumption of the automatic retracted position thereof to displace the same laterally in the direction of said slot extension portion whereby said plunger registers only with and automatically advances from retracted position only into said one slot.

5. Latching means comprising actuator and plunger plates disposed side by side and slidable relatively independently of and together with one another, said plunger plate having a protruding end and being capable of relative movement of separation laterally of the actuator plate, a plurality of cam means between the plates effective to separate the same when one of the plates slides independently relative to the other, and a cooperating striker plate adjacent the actuator and plunger plates and having plunger receiving slots of different lengths, only one of which registers with the protruding end of the plunger plate when the latter is separated from the actuator plate.

6. Latching means comprising actuator and plunger plates disposed side by side and slidable relatively independently of and together with one another, said plunger plate having an end protruding beyond the corresponding end of the actuator plate, cam means between the plates effective to separate the same in a lateral direction when one of the plates slides independently relative to the other, and a striker cooperatively disposed adjacent the actuator and plunger plates and having plunger receiving openings of different dimensions, only one of which has dimensions which register with the protruding end of the plunger plate when the latter is separated from the actuator plate.

7. Latching means comprising slidably mounted actuator and plunger plates disposed side by side, a striker formed with plunger receiving slots of different lengths and having a cam surface engageable with the plunger plate to retract same independently of the actuator plate, and meshing teeth between the actuator and plunger plates having wedging surfaces for separating the same and shifting the plunger plate laterally while being retracted by the striker cam whereby the plunger and only one plunger receiving slot are properly aligned for interfitting reception when opposite to one another.

8. Latching means comprising slidably mounted actuator and plunger plates disposed side by side, means establishing cooperation between the plates to form a one way connection effective whereby one of the plates moves conjointly with the other when said other plate is slidably retracted and whereby the said other plate slidably advances alone when the path of said one plate is obstructed by metal, and an apertured metal striker plate surface movable through a path wherein it obstructs the path of advance of said one plate, at least one of the aper- 8 tures in said striker plate presenting an unobstructed area conforming to the said path of advance of said one plate.

9. In combination, locking and striker structures movable relative to one another such that the path of relative movement is parallel to the plane of the latter, said locking structure comprising first and second plates slidable under actuation, means for actuating the first plate, lug means between the plates and engageable to carry the second plate with the first when the latter is actuated, and wedge means between the plates and engageable to separate the same laterally when they slide relative to one another, said striker structure comprising a third plate having wedge means at an actuating edge and a row of successive long andshort slot means spaced from the edge for receiving the second plate, the respective wedge means on said structures cooperating during relative movement between the structures to Wedge said second plate in a direction of motion longitudinally and laterally with respect to the first plate such that the former is registrable only with the long slot means.

10. In combination, locking and striker structures movable relative to one another in a manner whereby the path of movement of the striker structure coincides with the plane thereof, said locking structure comprising first and second slidable plates, dual control means for actuating the first plate from separate remote locations, lug means between the plates and engageable to carry the second plate with the first when the latter is actuated, and wedge means between the plates and engageable to sepa rate the same laterally when they slide relative to one another, said striker structure comprising a third plate having wedge means at the leading edge thereof and a row of successive slot means of differing lengths there following for receiving the second plate, the respective wedge means on said structures cooperating when the striker structure moves to wedge said second plate longitudinally and laterally with respect to the first plate such that the second plate is registrable only with the longer slot means in said row.

11. In a locking device, an actuator plate mounted for guided reciprocable movement, a plunger plate adjacent the actuator plate, means forming a one way connection between the plates whereby the plunger plate partakes of joint movement with the actuator plate when the latter is retracted in guided reciprocation and whereby the actuator plate remains stationary and deflects the plunger plate diagonally when the latter is retracted, and return spring means opposing diagonal deflection of the plunger plate. 12. In a locking device, an actuator plate mounted for guided reciprocable movement, a plunger plate adjacent the actuator plate means forming a one way connection between the plates whereby the plunger plate partakes of joint movement with the actuator plate when the latter is retracted in guided reciprocation and whereby the actuator plate remains stationary and deflects the plunger plate diagonally when the latter is retracted, bell crank means for opposing diagonal deflection of the plunger plate, and single spring means for urging said bell crank means into engagement with the plunger plate.

13. In a locking device, a retractable plunger plate, an actuator plate mounted for guided reciprocable movement, at one side of the plunger plate, teeth means forming a one way connection between the plates whereby the plunger plate partakes of joint movement with the actuator plate when the latter is retracted in guided reciprocation and whereby the actuator plate remains stationary and deflects the plunger plate diagonally by means of unrneshing the teeth when the plunger plate is independently retracted, a plurality of bell crank means on the opposite side of the plunger plate, each having one arm engaging the latter and having a spring means connecting their other arms to bias the one arm for forcing the teeth 9 means back into mesh between the plates against the force 2,118,690 of the diagonal deflecting motion of the plunger plate. 2,515,261

References Cited in the file of this patent n UNITED STATES PATENTS 5 398737 1,753,513 Hansen April 8, 1930 Whedon May 24, 1938 Poskin July 18, 1950 FOREIGN PATENTS Great Britain Sept. 21, 1933 

